Trailer wire rating -> Spotlights

[TuffRR]

I'm just in the process of planning how I will wire up 5 lights on the roof of my Discovery.

Ideally, I would like to use trailer wire to keep the wiring as clean and simple as possible although I have concerns that it will not pass enough current. At this stage I'm assuming that the globes will be max 100 watts so approx. 8.5 amps per light.

I've found some 7 core trailer wire (on the net) which is 5mm2 per core. This is the largest gauge wire I have found in 7 core. Unfortunately, it doesn't indicate its amp rating.

From what I can work out, most other 7 core is 3mm2 which I assume (from a few other threads on here) is insufficient for spotties at 100 watts.

Should I just give up on the idea of using trailer wire and run 3 lots of 2 core?

Thanks.

[chimpboy]

I'm just in the process of planning how I will wire up 5 lights on the roof of my Discovery.

Ideally, I would like to use trailer wire to keep the wiring as clean and simple as possible although I have concerns that it will not pass enough current. At this stage I'm assuming that the globes will be max 100 watts so approx. 8.5 amps per light.

I've found some 7 core trailer wire (on the net) which is 5mm2 per core. This is the largest gauge wire I have found in 7 core. Unfortunately, it doesn't indicate its amp rating.

From what I can work out, most other 7 core is 3mm2 which I assume (from a few other threads on here) is insufficient for spotties at 100 watts.

Should I just give up on the idea of using trailer wire and run 3 lots of 2 core?

Thanks.

Mmm, I used trailer wire for my roof lights - five core, PLUS a fat red and a fat white wire for the +ve and -ve. Then I used relays mounted on the roof rack itself to trip the lights, so effectively the trailer wire became signal wire for the relays, and the real power was carried by the red and white wires. But I didn't have the heavy kind of trailer wire you're describing.

If you can get 5mm^2 wire, then I think that would be heaps in the real world. You have five lights, you could probably run something like:

Wires 1&2: +12V for the two outer lights
Wires 2,3,4: +12V for the three inner lights
Wires 5,6,7: GND for all five lights

Then terminate the ground as early as possible (to keep it as short as possible).

That is pretty decent cabling for a few spotlights, and a good compromise for neatness of the wiring imho.

BTW, I am ditching my rooflights, they are not worth the hassle to me. If you haven't mounted them on the roof yet, do some test runs with different positions, at night. The need to be a fair way back from the windscreen or you will be amazed how much light comes straight down into your face, making it harder to see instead of easier. Ideally you want them far enough back that the roof of the car casts a shadow right across the bonnet, so there's no reflected light.

Nobody told me this when I first did mine on the SWB maverick, it only came good when I used the same roofrack on a LWB, which moved the lights back two feet

[-Scott-]

5mm2? HEAPS for a 100W light!
2 or 3 100W lights per core would be OK for most people.

Can you do a chassis return?

Scott

[Loanrangie]

More importantly, what are you trying to do ? Replicate a night game at the G in the bush ?

[RRturboD]

Before you setup the roof lights, consider that I installed HID conversions in my Super Oscars, mounted on the bull bar, gave me SO much light I gave up the idea of roof lights. If you want roof lights, try two HID on the roof, only draw about 40w each and create SERIOUS output.

[DamTriton]

Being discussed on another thread.

also Googled and found: http://www.epanorama.net/documents/wiri ... tance.html

AWG, Feet/Ohm, Ohms/100ft, Ampacity*, mm^2, Meters/Ohm, Ohms/100M

10______490.2______.204_____30____2.588_____149.5______.669
12______308.7______.324_____20____2.053______94.1______1.06
14______193.8______.516_____15____1.628______59.1______1.69
16______122.3______.818_____10____1.291______37.3______2.68
18_______76.8______1.30_____5_____1.024______23.4______4.27
20_______48.1______2.08_____3.3___0.812_______14.7_____6.82
22_______30.3______3.30_____2.1___0.644_______9.24_____10.8
24_______19.1______5.24_____1.3___0.511_______5.82_____17.2
26_______12.0______8.32_____0.8___0.405_______3.66_____27.3
28_______7.55______13.2_____0.5___0.321_______2.30______3.4


Wire Gauge Resistance per foot

4 .000292
6 .000465
8 .000739
10 .00118
12 .00187
14 .00297
16 .00473
18 .00751
20 .0119
22 .0190
24 .0302
26 .0480
28 .0764


Further down the page there is a distance/guage/current chart as well for the Doofs but appropriate to lighting